I know this is an old thread, but I stumbled onto it while googling load data for the 300 MP with 180 grain 44 mag bullets.

There is no load data for the 180 grain bullet and this powder. Alliant's book has 29 grains 300 MP for the 200 grain bullet. 25 grains powder for the 210 grain bullet. 22 grains powder for the 300 grain bullet.

The charges are all maximum loads.

Where would be a safe starting point for the 180 grain?